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Posted

have a question a quick one - how to model (but really model a rope)

 

you can get two or three basic threads that when curved in a helix can be made into a rope, but how to make all those little lines /threads/ - they can be made by textures (+bump) but is there a way to model them

i'm thinking it's impossible since it almost appears you need to make a helix with gzillion turns and have it bend by a helix, and don't see how you can make that

 

i'm posting a quick photo as a reference so you get a better understanding of my question

 

p.s. i know that the file size of this model would be like the combined weight of the empire state building and people in it, but i'm just wondering :)

rope_closeup.jpg

Posted

I think your prediction about file size would be correct. Even just these double winding paths contain a lot of information. Creating swept solids would hyper-inflate file size. :shock:

 

It was kind of fun playing around in Rhino3d to find a method to accomplish this. It would likely be quite a bit more complicated via AutoCAD: Maybe even requiring a spreadsheet setup to derive the individual spline fit-points.

RopePaths.dwg

Posted

i guess making a spreadsheet setup with each individual spline point wouldn't require a nuclear physicist but not far from it :)

 

i was doing a model of grapes, let's just say that making the stem took longer than i anticipated since i was creating 3D spline on the fly by inserting (x,y,z) point by point. Luckily i had around 24 points in that spline so it wasn't as intense as it could have been

 

making this would be a different story

Posted
i guess making a spreadsheet setup with each individual spline point wouldn't require a nuclear physicist but not far from it :)

 

i was doing a model of grapes, let's just say that making the stem took longer than i anticipated since i was creating 3D spline on the fly by inserting (x,y,z) point by point. Luckily i had around 24 points in that spline so it wasn't as intense as it could have been

 

making this would be a different story

 

As you alluded to earlier, a rope demonstrated as a texture mapped solid, with perhaps one level of twist in the geometry, would generally serve the purpose. I can’t imagine any practical reason to go to the next level of detail.

Posted
As you alluded to earlier, a rope demonstrated as a texture mapped solid, with perhaps one level of twist in the geometry, would generally serve the purpose. I can’t imagine any practical reason to go to the next level of detail.

 

pushing the limits of Autocad and loving to see it squirm and sweat... ofc it might be because i like to torture myself in doing things that have no real meaning :)

 

ofc it's always fun to try to reach the sky, even if it's a simple rope :?

 

4 days ago i made 2584 bricks in acad making 4 walls of a house - ofc they had filleted edges and may i say it was a horrid experience to do anything from zoomin in and out to saving- everything took 10-30 min for each of those things. yesterday instead of giving up, i x-refed some elements, others were blocks and i've downgraded some display resolution and was able to almost smoothly get 6400 light bulbs on a ferris wheel model i did - i would call that progress that can't happen without doing silly things

Posted

Point taken.

 

With 64 bit becoming the norm, and even 128 bit computing as a distinct possibility, what constitutes “sensible level of detail” may be changing.

 

6400 lights would certainly have been considered excessive just a few years ago.

Posted
... progress that can't happen without doing silly things

 

If you are a student you might want to try one of the next-generation Autodesk 3D products. www.autodesk.com/edcommunity

 

I did this in about 5 minutes in Inventor. I imagine if I experimented a bit more it would look closer to real rather than cosmetic texture.

Rope.png

Posted

I wrote an Autolisp routine to model rope as a surface entity extruded along a 3DPOLY path. Fun project. Limited to 255 vertices and you have to make a profile. But it worked. -David

ROPE0.JPG

ROPE1.JPG

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